What Causes Muscle Spasms? | Florida Orthopaedic Institute Skip to main content

What Causes Muscle Spasms?


Muscle spasms are involuntary contractions of a muscle. They occur suddenly and do not relax for a few seconds to several minutes. Additionally, several factors or triggers may cause muscle spasms, such as strenuous exercise and dehydration. In most cases, muscle spasms can be treated with home remedies, but it is possible that the muscle spasms are actually a symptom of another condition that needs medical treatment. It is important to regularly stretch and condition your muscles to prevent muscle spasms all together.


Muscles are bundles of fibers that contract and expand, which causes movement. When these muscles are regularly stretched and conditioned, their bundles of fibers lengthen, allowing them to contract and tighten more vigorously during exercise. On the other hand, muscles that are poorly conditioned are more susceptible to fatigue, which can alter spinal neural reflex activity. When muscles are fatigued, their oxygen supply is depleted, leading to the buildup of waste product and spasms. When a cramp begins, the spinal cord stimulates the muscle to keep contracting.


A muscle spasm, also known as a muscle cramp or “charley horse,” is an involuntary contraction of a muscle that occurs suddenly and does not relax. Although muscle spasms can happen to any muscle, the most commonly affected muscle groups are:

  • Back of lower leg/calf.
  • Back of thigh.
  • Front of thigh.
  • Feet, hands, and arms.
  • Abdomen and ribcage.
Muscle Spasms Graphic

That said, the exact cause of muscle spasms is unknown. However, some researchers believe factors such as poor stretching and conditioning, muscle fatigue, exercising or working in intense heat, dehydration, and depletion of salt and electrolytes contribute to muscle spasms.

Those who are at the highest risk of getting muscle spasms include infants, young children, and people over the age of 65. Additionally, other factors that can put people at a greater risk for muscle spasms include:

  • Certain medications.
  • Being overweight.
  • Illness.
  • Overexerting during work or exercise.

Muscle spasms are most common among athletes – specifically endurance athletes like marathon runners.

Muscle Spasms Informational Graphic


Muscle spasms range in intensity and can be mild to extremely painful. When experiencing a muscle spasm, it may cause the muscle to feel hard to the touch, appear visibly distorted, or twitch. These spasms can last anywhere from a few minutes to a few hours and may reoccur many times before they entirely go away.

Home Treatments

Muscle spasms usually go away on their own without having to see a doctor. However, when a muscle spasm occurs, you should:

  • Stop whatever activity triggered the cramp.
  • Gently stretch and massage the muscle, holding it in a stretched position until the cramp goes away.
  • Apply heat to tight/tense muscles.


Although most muscle cramps are non-threatening, sometimes they can indicate a serious medical condition. See your Florida Orthopaedic Institute physician if your cramps are severe, happen frequently, respond poorly to simple treatments, or are not related to obvious causes like strenuous exercise. It is possible that you may have problems with circulation, metabolism, hormones, nerves, nutrition, or medications.

Muscle spasms can be a symptom of many conditions that range from minor to severe, such as spinal nerve irritation or compression, thyroid disease, narrowing of the spinal canal, hardening of the arteries, chronic infections, cirrhosis of the liver and Lou Gehrig’s disease.

Your Florida Orthopaedic Institute physician will check all other symptoms you may have, decide what your exact condition is, and create a treatment plan based off of the results of your diagnosis.

Next Steps

To avoid future cramps, do regular flexibility stretches and exercises before and after you work out to stretch muscle groups most prone to cramping. Some of the best muscles to stretch are the calves, hamstring, quadriceps.

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